The long range goal of this project is to elucidate the mechanism of nonspecific integrative recombination in bacteriophage Mu. Specific objectives include 1) analysis of the effects of induction on the conformation and composition of a plasmid containing a heat-inducible Mu prophage; 2) characterization of the structure and fate of the products of early Mu replication; 3) evaluation of the hypothesis that replication forks in host chromosomes are target sites for integration of Mu prophage; and 4) investigation of the origin and function of heterogeneous circular (Hc) DNA in Mu DNA replication.